BUDGET JUSTIFICATION - Collaboration Development Fund We request $135,000 per year to establish a Collaboration Development Fund. A wide range of collaborators will be enlisted to help further identify and validate HIV-host protein complexes, facilitate structure determination of the complexes, utilize structural information to more deeply probe the biological functions of the HIV regulatory and accessory proteins, and extend technological developments in high-throughput expression, structure determination, MS methods, cryo-EM, and tomography. One way in which we will facilitate essential collaborations will be to provide seed funding for promising studies. These studies may include reagent preparation, mutagenesis, biochemical, functional, or virological experiments, methods to identify and validate new complexes, or other methods development. The requested Fund will provide flexibility to engage in new directions and will be used primarily to fund sub-contracts with outside investigators, as determined in consultation with our advisory committees and with NIGMS approval. Funds in this category also will be allocated to visits of existing and potential collaborators to the HARC Center to plan future research directions.